Cell free nucleic acids (cfNA) are genetic sequences. They are not attached to cells. They can be found circulating in the blood. These acids can be used to detect mutations in genetic sequences and can thereby be used as a 'liquid biopsy' tool for diagnosis of several types of cancer.
Scientists from University of Toronto have developed a simple method of analyzing the amount of mutated cfNA present in patient blood.
The study details the fabrication of an electrochemical clamp assay targeted towards detecting mutations in the KRAS gene, which causes lung, colorectal and ovarian cancer. The assay works by mixing in clamps that are specific for all other mutations except the mutation of interest, leading to a solution that has only the target mutation free of clamps.
This solution is then applied to a sensor, where the target mutation binds, and is detected with the help of an electrochemical sensor. The other mutations which have been clamped are not able to bind to the sensor and are finally washed away.
The electrochemical clamp assay requires much less volumes of serum, and can be performed on undiluted serum, which leads to simplicity in workflow and minimized sample loss. Also, the test can produce results in as little as 5 minutes, and can cut down on significant costs involved in cancer diagnosis.